# System1 Models

> Low-cost hosted decision models for routing, classification and scoring. One Jev-compatible API, with Global and EU tiers.

Sign in with Google at https://system1models.ai/login, create an API key in your dashboard and start with 100M input tokens free. Prepaid credit top-ups use Stripe with invoices. Top-ups: Germany today; EU businesses and more countries soon.

## Models and launch pricing
s1-fast (Plumb-4B, text): Global $0.025 / EU $0.034 per 1M input tokens; output tokens free.
s1-pro (Winnow-12B Q8, text): Global $0.034 / EU $0.040 per 1M input tokens; output tokens free.
Image input: coming soon. USD rates exclude applicable taxes. EUR rates are published at https://system1models.ai/pricing.

## Tiers and data
Today both tiers run in Finland: API gateway on Hetzner in Helsinki, GPU inference on Verda in Finland. Global has lower priority on shared EU capacity. Client-to-API TLS 1.3; gateway-to-GPU WireGuard encryption. Prompts and outputs are never stored or used for training.
The decentralized Global network is rolling out; it carries no customer traffic today. We will announce before Global traffic moves to the network. EU inference stays on contracted EU operators and never uses that network.

## API and MCP
API base: https://api.system1models.ai
POST /v1/systemone: model, state, and exactly one typed question (noul, choice or score).
GET /v1/models (alias /models): live model registry.
Authenticate inference with Authorization: Bearer <API key>; choose S1-Region: global|eu.
Hosted MCP: https://api.system1models.ai/mcp (streamable HTTP, JSON-RPC; Bearer API key). Tools: decide, list_models, get_usage, get_balance.
Swagger UI: https://system1models.ai/docs/api/reference
OpenAPI snapshot: https://system1models.ai/openapi.json
Authoritative API OpenAPI: https://api.system1models.ai/openapi.json

## Resources
- [llms.txt](https://system1models.ai/llms.txt)
- [llms-full.txt](https://system1models.ai/llms-full.txt)
- [Sign in and create a key](https://system1models.ai/login?next=/dashboard)
- [Quickstart](https://system1models.ai/docs/quickstart)
- [API reference (Swagger UI)](https://system1models.ai/docs/api/reference)
- [OpenAPI JSON](https://system1models.ai/openapi.json)
- [Hosted MCP setup](https://system1models.ai/mcp)
- [Models](https://system1models.ai/models)
- [Launch pricing](https://system1models.ai/pricing)
- [EU tier](https://system1models.ai/eu)
- [Agent guide](https://system1models.ai/agents)
- [DPA](https://system1models.ai/legal/dpa)
- [Sub-processors](https://system1models.ai/legal/subprocessors)
- [Security](https://system1models.ai/security)